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Portal alumni
(2009)
Liebe Leserin, lieber Leser, wenn es nach der Bundesfamilienrninisterin geht, soll Deutschland eines der familienfreundlichsten Länder in Europa werden. Noch sieht die Realität allerdings anders aus. Wie Ehemalige sich zwischen familiären und beruflichen Optionen entschieden haben, welche Probleme sie zu bewältigen hatten und welche Lösungen sie fanden, davon berichten sie in unserem Titelthema. Jede dritte Akademikerin bleibt heute in Deutschland kinderlos, Tendenz steigend. Abgesehen davon, dass es auch schlichtweg Lebensentwürfe ohne Kinder gibt: Ein nicht unwesentlicher Grund dafur ist sicherlich, dass die größte Last bei der Kindererziehung immer noch Frauen tragen und sie deshalb auch die größeren Einbußen in ihrer Karriere haben. So herrscht bei vielen Arbeitgebern das Vorurteil, Mütter in Führungspositionen wären weniger leistungsfahig. Dass aber gerade eine Familie Frauen in verantwortungsvollen Positionen den Rücken stärken und zu noch größerem Einsatz beflügeln kann, davon berichtet der einführende Artikel. Ein Beispiel dafür, dass sich Familie und eine berufliche Führungsposition vereinbaren lassen, ist auch Uni-Präsidentin, Prof. Dr.-Ing. Dr. Sabine Kunst. In einem Interview verrät sie ihr ganz persönliches Erfolgsrezept und stellt außerdem die strategische Ausrichtung der Hochschule in den nächsten Jahren vor. Wenn Sie Ihre Erfahrungen zu unserem Titelthema mit anderen Ehemaligen diskutieren wollen, können Sie dies unter .. Forum" in unserem "alumni-portal" tun. Wie immer freuen wir uns auf Ihre Meinung zur vorliegenden Ausgabe von ,,Portal alurnni" und wünschen Ihnen viele Vergnügen beim Lesen. Viele Grüße aus Potsdam, Ihr Alumni-Team.
Deforestation is a prominent anthropogenic cause of erosive overland flow and slope instability, boosting rates of soil erosion and concomitant sediment flux. Conventional methods of gauging or estimating post-logging sediment flux often focus on annual timescales but overlook potentially important process response on shorter intervals immediately following timber harvest. We resolve such dynamics with non-parametric quantile regression forests (QRF) based on high-frequency (3 min) discharge measurements and sediment concentration data sampled every 30-60 min in similar-sized (similar to 0.1 km(2)) forested Chilean catchments that were logged during either the rainy or the dry season. The method of QRF builds on the random forest algorithm, and combines quantile regression with repeated random sub-sampling of both cases and predictors. The algorithm belongs to the family of decision-tree classifiers, which allow quantifying relevant predictors in high-dimensional parameter space. We find that, where no logging occurred, similar to 80% of the total sediment load was transported during extremely variable runoff events during only 5% of the monitoring period. In particular, dry-season logging dampened the relative role of these rare, extreme sediment-transport events by increasing load efficiency during more efficient moderate events. We show that QRFs outperform traditional sediment rating curves (SRCs) in terms of accurately simulating short-term dynamics of sediment flux, and conclude that QRF may reliably support forest management recommendations by providing robust simulations of post-logging response of water and sediment fluxes at high temporal resolution.
The 933 km(2) Bengue catchment in northeastern Brazil is characterized by distinct rainy and dry seasons. Precipitation is stored in variously sized reservoirs, which is essential for the local population. In this study, we used TerraSAR-X SM(HH) data for an one-year monitoring of seasonal changes in the reservoir areas from July 2011 to July 2012. The monitoring was based on acquisitions in the ascending pass direction, complemented by occasional descending-pass images. To detect water surface areas, a histogram analysis followed by a global threshold classification was performed, and the results were validated using in situ GPS data. Distinguishing between small reservoirs and similar looking dark areas was difficult. Therefore, we tested several approaches for identifying misclassified areas. An analysis of the surface area dynamics of the reservoirs indicated high spatial and temporal heterogeneities and a large decrease in the total water surface area of the reservoirs in the catchment by approximately 30% within one year.
Cosmic-ray neutron sensing (CRNS) is a non-invasive tool for measuring hydrogen pools such as soil moisture, snow or vegetation. The intrinsic integration over a radial hectare-scale footprint is a clear advantage for averaging out small-scale heterogeneity, but on the other hand the data may become hard to interpret in complex terrain with patchy land use.
This study presents a directional shielding approach to prevent neutrons from certain angles from being counted while counting neutrons entering the detector from other angles and explores its potential to gain a sharper horizontal view on the surrounding soil moisture distribution.
Using the Monte Carlo code URANOS (Ultra Rapid Neutron-Only Simulation), we modelled the effect of additional polyethylene shields on the horizontal field of view and assessed its impact on the epithermal count rate, propagated uncertainties and aggregation time.
The results demonstrate that directional CRNS measurements are strongly dominated by isotropic neutron transport, which dilutes the signal of the targeted direction especially from the far field. For typical count rates of customary CRNS stations, directional shielding of half-spaces could not lead to acceptable precision at a daily time resolution. However, the mere statistical distinction of two rates should be feasible.
Cosmic-ray neutron sensing (CRNS) is a non-invasive tool for measuring hydrogen pools such as soil moisture, snow or vegetation. The intrinsic integration over a radial hectare-scale footprint is a clear advantage for averaging out small-scale heterogeneity, but on the other hand the data may become hard to interpret in complex terrain with patchy land use.
This study presents a directional shielding approach to prevent neutrons from certain angles from being counted while counting neutrons entering the detector from other angles and explores its potential to gain a sharper horizontal view on the surrounding soil moisture distribution.
Using the Monte Carlo code URANOS (Ultra Rapid Neutron-Only Simulation), we modelled the effect of additional polyethylene shields on the horizontal field of view and assessed its impact on the epithermal count rate, propagated uncertainties and aggregation time.
The results demonstrate that directional CRNS measurements are strongly dominated by isotropic neutron transport, which dilutes the signal of the targeted direction especially from the far field. For typical count rates of customary CRNS stations, directional shielding of half-spaces could not lead to acceptable precision at a daily time resolution. However, the mere statistical distinction of two rates should be feasible.